Perfluoroalkylalkylcarboxylic acids, process for their manufacture and their use

ABSTRACT

New perfluoroalkylalkylcarboxylic acids of the formula ##EQU1## are provided, wherein R f  is an unbranched or branched perfluoroalkyl radical with 3 to 18 carbon atoms, R 1  is hydrogen or fluorine and m is a whole number from 1 to 3. 
     The new compounds are suitable for producing water and oil-repellent finishes, soil-release and antisoiling effects on porous and non-porous substrates. They are further valuable intermediates for the manufacture of fluorinated compounds which may be used in the same field as the inventive compounds.

French Pat. No. 2.070.452 teaches the manufacture ofperfluoroalkylalkylcarboxylic acids by hydrolysis of correspondingnitriles according to the following reaction equation:

    C.sub.n F.sub.2n.sub.+1 (CH.sub.2).sub.a CN .sup.H.sbsp.2.sup.O → C.sub.n F.sub.2n.sub.+1 (CH.sub.2).sub.a COOH + NH.sub.3

the present invention provides new perfluoroalkylalkylcarboxylic acidsof the formula ##EQU2## wherein R_(f) is an unbranched or branchedperfluoroalkyl radical with 3 to 18 carbon atoms, R₁ is hydrogen orfluorine, and m is a whole number from 1 to 3.

The unbranched or branched perfluoroalkyl radical can have e.g. thefollowing formulae:F(CH₂)_(p) -- p = 3 - 18(CF₃)₂ CF(CF₂)_(q) -- q = 1 -15CF₃ [CF₂ CF(CF₃)]_(r) -- r = 1 - 5(CF₃)₂ CF[CF₂ CF(CF₃)]_(s) -- s =1 - 5

Preferably the perfluoroalkyl radicals contain from 3 to 14 or from 4 to12 carbon atoms, e.g. C₄ F₉, C₆ F₁₃, C₈ F₁₇, C₁₀ F₂₁, C₁₂ F₂₅ or (CF₃)₂CF(CF₂)_(q) _('), wherein q' is a whole number from 1 to 9.

R₁ is hydrogen or fluorine, preferably fluorine, and m is a whole numberfrom 1 to 3, preferably 1.

The perfluoroalkylalkylcarboxylic acids according to the inventionpreferably have the formula ##EQU3## wherein R is hydrogen or fluorine,n is a whole number from 3 to 14, and m is a whole number from 1 to 3.

Particularly suitable are also the acids of the formulae ##EQU4##

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+.sub.1 CH.sub.2 CF.sub.2 CH.sub.2 CH.sub.2 COOH,                                            (5)

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1 .sub.+.sub.1 CH.sub.2 CHF CH.sub.2 CH.sub.2 COOH,                                                     (6)

    c.sub.n.sbsb.1 F.sub.2n.sub.1 .sub.+.sub.1 (CH.sub.2 CF.sub.2).sub.2 CH.sub.2 CH.sub.2 COOH and                                (7)

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+.sub.1 (CH.sub.2 CHF).sub.2 CH.sub.2 CH.sub.2 COOH,                                            (8)

wherein R₁ is hydrogen or fluorine, n₁ is a whole number from 4 to 12,preferably from 6 to 10, and m is a whole number from 1 to 3.

The perfluoroalkylalkylcarboxylic acids according to the invention aremanufactured by hydrolysing perfluoroalkylalkyl nitriles of the formula##EQU5## wherein R_(f) is an unbranched or branched perfluoroalkylradical with 3 to 18 carbon atoms, R₁ is hydrogen or fluorine, and m isa whole number from 1 to 3, in the presence of inorganic or organicacids.

The perfluoroalkylalkyl nitriles that are preferably used have theformulae ##EQU6##

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+.sub.1 CH.sub.2 CF.sub.2 CH.sub.2 CH.sub.2 CN,                                              (12)

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+.sub.1 (CH.sub.2 CF.sub.2).sub.2 CH.sub.2 CH.sub.2 CN,                                     (13)

    c.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+.sub.1 CH.sub.2 CHF CH.sub.2 CH.sub.2 CN and                                                    (14)

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+.sub.1 (CH.sub.2 CHF).sub.2 CH.sub.2 CH.sub.2 CN,                                              (15)

wherein n, n₁, m and R₁ have the indicated meanings.

Suitable acids are, for example, sulphuric acid, hydrochloric acid,formic acid, or acetic acid.

The reaction is carried out at temperatures of about 50° to 200°C,preferably 80° to 180°C, and either in a solvent or without a solvent.Preferably no solvent is used. The reaction mixture is ordinarily in theform of an emulsion of the perfluoroalkylalkyl nitrile in the acid.

The acid is simultaneously reaction medium and reagent. The amount of itis therefore expediently so chosen that a multiple molar surplus isused, based on the perfluoroalkylalkyl nitrile. The reaction time can beabout 5 to 30, preferably 10 to 20, hours.

The perfluoroalkylalkyl nitriles used as starting products are obtainedby addition of vinylidene or vinyl fluoride, and subsequently ofethylene, to perfluoroalkyl iodides of the formula R_(f) I, and byreaction in a further reaction step with a metal cyanide.

The compounds according to the invention are suitable for producing oiland water repellent finishes on porous and non-porous substrates, alsofor obtaining soil release and antisoiling effects. In addition they canbe used as intermediates for the manufacture of further valuablefluorinated end products. These end products are obtained for example,by a modification of the carboxyl group by known chemical reactions.

By porous substrates are meant, for example, leather, paper and wood,but preferably textile fabrics, whereas suitable non-porous materialsare surfaces of glass, metal, and plastic. The compounds according tothe invention can also be used, for example, as additives for oil andlubricants for preventing wear and corrosion, or as lubricants, asadditives for polishes and waxes, and as surface-active assistants.

The compounds according to the invention can be used in particular forfinishing textile fabrics, for example those made from natural andregenerated cellulose, e.g. cotton, linen, staple fibre, or celluloseacetate, also those made from wool, synthetic polyamides, polyesters,polypropylene and polyacrylonitrile, and also the corresponding fibreblends.

The textile fabrics can be in any desired form of processing, forexample as fibres, threads, tops, woven and knitted fabrics.

The compounds according to the invention are applied from solventliquors by the immersion process, also by padding, spraying,slop-padding, immersion in a melt, spraying with heat fixing or also bytransfer from an auxiliary material (paper, foil) accompanied by theapplication of heat.

The compounds according to the invention are applied in amounts of about0.05 to 10, preferably 0.1 to 5, percent by weights, based on the weightof the substrates.

The following Examples will serve to illustrate the invention but do notimply any limitation thereof. Parts and percentages are by weight.

EXAMPLE 1

35 G of the nitrile of the formula CF₃ (CF₂)_(n) (CH₂ CF₂)_(o) CH₂ CH₂CN (n = 5, 7, 9; o = 1, 2, 3) are emulsified in 100 ml of sulphuric acidand heated to 140°C over the course of 20 hours. The emulsion is thenpoured on ice. The aqueous phase is then extracted with diethyl etherand the ethereal phase is dried over sodium sulphate. The solvent isdistilled off to yield the acid of the formula

    (101) CF.sub.3 (CF.sub.2).sub.n (CH.sub.2 CF.sub.2).sub.o CH.sub.2 CH.sub.2 COOH.

Yield: 34.2 g of white powder.

Melting point: 93°-95°C.

Acid titer: 56.7 g of NaOH/kg of acid.

Example 2

39 G of the nitrile of the formula

    CF.sub.3 (CF.sub.2).sub.n CH.sub.2 CHF CH.sub.2 CH.sub.2 CN (n = 5, 7, 9)

are emulsified in 100 ml of sulphuric acid (75%). The emulsion is thenpoured on ice. The aqueous phase is then extracted with diethyl etherand the ethereal phase is dried over sodium sulphate. The solvent isdistilled off to yield the acid of the formula

    (102) CF.sub.3 (CF.sub.2).sub.n CH.sub.2 CHFCH.sub.2 CH.sub.2 COOH.

yield: 36.6 g of light brown powder.

Melting point: 67°-77°C.

Acid titer: 63 g of NaOH/kg of acid.

EXAMPLE 3

Cotton, cotton/polyester (35/66) and polyamide fabrics are thoroughlyimpregnated with a 1% solution of the compounds of the formulae (101)and (102), squeezed out, and left to dry in the air. In the 3-M test thetreated fabrics exhibit oil repellencies of 100 to 110 (untreatedfabric: 0). (3-M oil repellency test, E. J. Grajeck, W. H. Peterson,Textile Research Journal 32, 320-331, 1960. The test is carried out withheptane/nujol mixtures and evaluated with ratings from 0 to 150; 150 isthe rating that indicates the best oil repellency).

I claim:
 1. A perfluoroalkylalkylcarboxylic acid of the formula ##EQU7##wherein R_(f) is an unbranched or branched perfluoroalkyl radical with 3to 18 carbon atoms, R₁ is hydrogen or fluorine, and m is a whole numberfrom 1 to
 3. 2. A perfluoroalkylalkylcarboxylic acid according to claim1, of the formula ##EQU8## wherein R₁ is hydrogen or fluorine, n is awhole number from 3 to 14, and m is a whole number from 1 to
 3. 3. Aperfluoroalkylalkylcarboxylic acid according to claim 2, of the formula##EQU9## wherein R₁ and m have the meanings given in claim 2 and n₁ is awhole number from 4 to
 12. 4. A perfluoroalkylalkylcarboxylic acidaccording to claim 3, of the formula ##EQU10## wherein R₁ and n₁ havethe meanings given in claim
 3. 5. A perfluoroalkylalkylcarboxylic acidaccording to claim 3, of the formulae

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+ 1 CH.sub.2 CHFCH.sub.2 CH.sub.2 COOH and

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+ 1 CH.sub.2 CF.sub.2 CH.sub.2 CH.sub.2 COOH

wherein n₁ is a whole number from 4 to
 12. 6. Aperfluoroalkylalkylcarboxylic acid according to claim 3, of the formulae

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+1 (CH.sub.2 CHF).sub.2 CH.sub.2 CH.sub.2 COOH and

    C.sub.n.sbsb.1 F.sub.2n.sbsb.1.sub.+ 1 (CH.sub.2 CF.sub.2).sub.2 CH.sub.2 CH.sub.2 COOH

wherein n₁ is a whole number from 4 to 12.